Electrically small planar UWB antenna apparatus and related system

Abstract

An electrically small, planar ultra wide bandwidth (UWB) antenna is disclosed. The antenna has a conductive outer ground area that encompasses a tapered non-conducting clearance area, which surrounds a conductive inner driven area. The feed is unbalanced with the terminals are across the narrowest part of the non-conducting clearance area which is tapered to provide a low VSWR across ultra wide bandwidths exceeding 100%. The antenna can be arrayed in 1D and 2D on a single common substrate. Amplifiers can be readily mounted at the feed.

What is claimed is:  
     
       1. An antenna device having ultra wide bandwidth (UWB) characteristics, comprising: 
       a ground element having a cutout section with an inner circumference, the inner circumference having a first shape; and  
       a driven element with an outer circumference having a second shape, the driven element being smaller in size than the cutout section and being situated within the cutout section to define a clearance area between the driven element and the ground element;  
       wherein the first shape is a first simple closed curve having no cusps,  
       wherein the second shape is a second simple closed curve having no cusps, including at least a concave portion and a convex portion,  
       wherein the first and second shapes are formed such that any radial line from the center point of the driven element will intersect the first shape at a single first intersection point, and will intersect the second shape at a single second intersection point, a distance on the radial line between the first and second intersection points being defined as a clearance width between the driven element and the ground element for the radial line, and  
       wherein the clearance area is tapered such that the clearance width between the driven element and the ground element is monotonically nondecreasing from a minimum clearance width to a maximum clearance width.  
     
     
       2. An antenna device, as recited in  claim 1 , further comprising a transmission line for providing an electrical signal to the driven element. 
     
     
       3. An antenna device, as recited in  claim 2 , wherein the transmission line is connected to the driven element at a feed point proximate to the minimum clearance width of the clearance area. 
     
     
       4. An antenna device, as recited in  claim 2 , wherein the transmission line comprises a metal layer. 
     
     
       5. An antenna device, as recited in  claim 2 , wherein the transmission line comprises a magnet wire. 
     
     
       6. An antenna device, as recited in  claim 2 , wherein the transmission line comprises a coaxial cable. 
     
     
       7. An antenna device, as recited in  claim 2 , wherein the transmission line is not coplanar with either the driven element or the ground element. 
     
     
       8. An antenna device, as recited in  claim 1 , wherein the clearance area is filled with one of FR-4, Teflon, fiberglass, or air. 
     
     
       9. An antenna device, as recited in  claim 1 , wherein the ground element and the driven element comprise a conductive material. 
     
     
       10. An antenna device, as recited in  claim 9 , wherein the conductive material is copper. 
     
     
       11. An antenna device, as recited in  claim 1 , wherein the first and second shapes are the same, except in different scale. 
     
     
       12. An antenna device, as recited in  claim 1 , wherein the concave portion of the second shape is formed proximate to the maximum clearance width. 
     
     
       13. An antenna device, as recited in  claim 1 , wherein the driven element has an axis of symmetry about a line that passes between the minimum clearance width of the clearance area and the maximum clearance width of the clearance area. 
     
     
       14. An antenna device, as recited in  claim 1 , wherein the concave portion of the second shape is centered on the axis of symmetry, proximate to the maximum clearance width. 
     
     
       15. An antenna device having ultra wide bandwidth (UWB) characteristics, comprising: 
       a ground element having a cutout section with an inner circumference, the inner circumference having a first shape; and  
       a driven element with an outer circumference having a second shape, the driven element being smaller in size than the cutout section and being situated within the cutout section to define a clearance area between the driven element and the ground element,  
       wherein the first shape is a first simple closed curve having no cusps, including at least a concave portion and a convex portion,  
       wherein the second shape is a second simple closed curve having no cusps, including at least a concave portion and a convex portion,  
       wherein the first and second shapes are formed such that any radial line from the center point of the driven element will intersect the first shape at a single first intersection point, and will intersect the second shape at a single second intersection point, a distance on the radial line between the first and second intersection points being defined as a clearance width between the driven element and the ground element for the radial line, and  
       wherein the clearance area is tapered such that the clearance width between the driven element and the ground element is monotonically nondecreasing from a minimum clearance width to a maximum clearance width.  
     
     
       16. An antenna device, as recited in  claim 15 , further comprising a transmission line for providing an electrical signal to the driven element. 
     
     
       17. An antenna device, as recited in  claim 16 , wherein the transmission line is connected to the driven element at a feed point proximate to the minimum clearance width of the clearance area. 
     
     
       18. An antenna device, as recited in  claim 17 , wherein the transmission line comprises a metal layer. 
     
     
       19. An antenna device, as recited in  claim 17 , wherein the transmission line comprises a magnet wire. 
     
     
       20. An antenna device, as recited in  claim 17 , wherein the transmission line comprises a coaxial cable. 
     
     
       21. An antenna device, as recited in  claim 17 , wherein the transmission line is not coplanar with either the driven element or the ground element. 
     
     
       22. An antenna device, as recited in  claim 15 , wherein the clearance area is filled with one of FR-4, Teflon, fiberglass, or air. 
     
     
       23. An antenna device, as recited in  claim 15 , wherein the ground element and the driven element comprise a conductive material. 
     
     
       24. An antenna device, as recited in  claim 23 , wherein the conductive material is copper. 
     
     
       25. An antenna device, as recited in  claim 15 , wherein the first and second shapes are the same, except in different scale. 
     
     
       26. An antenna device, as recited in  claim 15 , wherein the concave portion of the first shape is formed proximate to the maximum clearance width. 
     
     
       27. An antenna device, as recited in  claim 15 , wherein the driven element has an axis of symmetry about a line that passes between the minimum clearance width of the clearance area and the maximum clearance width of the clearance area. 
     
     
       28. An antenna device, as recited in  claim 15 , wherein the concave portion of the first shape is centered on the axis of symmetry, proximate to the maximum clearance width.